Think you know the answer to this theory test question?

You must use your dipped headlight when visibility is seriously reduced. In fog a film of mist can form over the outside of your visor or goggles. This can further reduce your ability to see. Be aware of this hazard and keep your visor or goggles clear.

Slow down and increase your following distance to the vehicle in front because your visibility will be less. If you are driving in freezing fog, be cautious of black ice.

You will need to be constantly scanning for potential exits, especially if the fog is thick, and be aware that as you only have one headlight and a much smaller profile, you will be less visible to other drivers than a vehicle with two headlights.